Semi-automatic pressurization mode is selected if which condition occurs?

Semi-automatic pressurization mode is selected if which condition occurs?

• A. In Flight
• B. In Manual Mode
• C. No FMGS Data Available to the CPCs
• D. On The Ground

Answer: (C)

The key idea is how the cabin pressurization system gets its targets. Normally, the CPCs rely on data from the FMGS to determine the desired cabin altitude and the rate of pressurization/depressurization. If that data flow from the FMGS to the CPCs is lost or unavailable, automatic scheduling can no longer be trusted, so the system switches to semi-automatic mode. In this mode, the crew can manually set or adjust the cabin pressure parameters while the CPCs continue to manage the hardware within safe limits. This provides a safe fallback so pressurization can still be controlled even with degraded FMGS data. The other situations—being in flight, being in manual mode by design, or being on the ground—don’t by themselves trigger semi-automatic mode. It’s specifically the lack of FMGS data available to the CPCs that calls for this fallback mode.

The key idea is how the cabin pressurization system gets its targets. Normally, the CPCs rely on data from the FMGS to determine the desired cabin altitude and the rate of pressurization/depressurization. If that data flow from the FMGS to the CPCs is lost or unavailable, automatic scheduling can no longer be trusted, so the system switches to semi-automatic mode. In this mode, the crew can manually set or adjust the cabin pressure parameters while the CPCs continue to manage the hardware within safe limits. This provides a safe fallback so pressurization can still be controlled even with degraded FMGS data.

The other situations—being in flight, being in manual mode by design, or being on the ground—don’t by themselves trigger semi-automatic mode. It’s specifically the lack of FMGS data available to the CPCs that calls for this fallback mode.